1. Field of Invention
The present invention relates to an engine system, and more particularly, to an engine system with maximized functions at low and middle speeds.
2. Description of Related Art
In general, it is known that a diesel engine has lower fuel consumption and higher efficiency than those of a gasoline engine. The diesel engine generally has efficiency of about 40%, which accords with a high compression ratio of the diesel engine.
Recently, in order to obtain higher output in the engine, a turbo charger, an intercooler, and the like are additionally included.
The engine adopting the turbo charger sucks and compresses exhaust gas or external air by using a compressor of the turbo charger, and in this case, the generated supercharged air (high temperature compressed air) is supplied to an engine.
However, the rapidly compressed air absorbs heat of the turbo charger and heat generated during the compression process, so that a density thereof is decreased, thereby degrading charging efficiency within a combustion chamber of the engine. Accordingly, it is possible to secure high density by cooling the supercharged air by using the intercooler, and as a result, the larger amount of air enters the combustion chamber of the engine, thereby obtaining a high output.
In the meantime, research on a decrease in fuel consumption and improvement of output torque in low and middle speed sections in respect to revolutions per minute of an engine in the engine including the turbo charger has been conducted, along with research on a more efficient control of supply of recirculated gas.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.